The present invention relates to an apparatus for off-loading incoherent material from a container.
The subject apparatus is usable, in particular, in the chemical and/or pharmaceutical industry and wherever containers housing in their interior incoherent material constituted by dusts, fine-grain granulates or similar products need to be off-loaded.
Such containers are emptied in correspondence with an off-loading station, wherefrom the material housed therein is transferred towards a collecting tank or a collector connected, for instance, to a machine that uses the incoherent material itself for subsequent work processes. The collecting tank is positioned at a given level, and it is sustained by a support structure able to allow the positioning of a container at another level, higher than the previous one, thereby allowing the emptying of the container itself by gravity.
To allow the material to flow out of the superior container into the inferior container, connecting means are provided between the two levels, usually constituted by a rigid cylindrical conduit positioned vertically, within which a tubular sack is usually coaxially inserted, such sack presenting its own extremities respectively connected, in a direct or indirect manner, to the discharge outlet of the container and to the loading outlet of the tank or hopper.
The container is emptied by the passage of the dust contained therein through the tubular sack, which must be connected in substantially hermetic manner to the container and to the hopper so as not to let the dust exit: in practice, the dispersion of the dusts into the environment needs to be contained as much as possible. The relevance of the problem described above is all the greater the more the dusts treated in the apparatus considered above are constituted by substances or chemical compounds which are not easily degradable in the environment and, in some case, potentially harmful.
For this reason it is necessary to use tubular sacks that differ from substance to substance and thoroughly to clean the connection when shifting from one substance to another. Usually, the superior extremity of the aforesaid cylindrical conduit is connected to the aforementioned container through a spacer element provided with an inner cavity developing along a vertical axis; to an intermediate portion of said spacer element is coaxially connected in air-tight fashion the superior extremity of the aforementioned tubular sack.
The inferior extremity of the aforesaid container supports a valve element usable to open or to close completely the inferior extremity itself; such valve element is usually constituted by a butterfly valve equipped with a substantially disk-shaped shutter element able to rotate in the two directions about a horizontal axis. To the inferior extremity of the aforementioned spacer element can be associated a removable shutter element, able completely to close, when present, the inferior extremity of the spacer element itself. Every time the incoherent material housed inside the container has completed flowing towards the collecting tank, and the apparatus in question needs to be used to handle a material differing from the one handled previously, all portions of the apparatus which have been in contact with the material must be perfectly cleaned, in correspondence with an appropriate washing station, to prevent any contamination of the new material to be handled.
For this purpose, in the first place, the aforementioned butterfly valve must be closed, the tubular sack must be removed, preferably after making it re-enter, in a way known in itself, into the aforesaid spacer element, and the shutter element must be so positioned as to close the inferior extremity of the spacer element itself. The aforementioned container and the spacer element are then removed to be taken to the washing station.
All the operations described above should take place, as mentioned, without the possibility of any pollution to the surrounding environment by residues of material present inside the container, the spacer element and the tubular sack. However, in reality, the face of the shutter element of the butterfly valve opposite the one defining the bottom of the container is soiled with material, which can easily be transferred to the environment while the container itself is being removed, and the superior extremity of the spacer element, also soiled, is open.
The aim of the present invention is to eliminate the aforementioned drawback, providing an apparatus for off-loading incoherent material from a container wherein the various aforementioned components can be removed from the apparatus itself without there being the possibility of any discharge of material, preventing cross-pollination between the aforementioned components and the external environment.
According to the present invention, an apparatus is obtained for off-loading incoherent material from a container, for the dispensing of the incoherent material itself along a determined feeding route and towards a user unit, comprising a valve organ positioned in correspondence with an outlet of said container and a conduit whose axis of development is parallel to said route, whose first extremity can be associated to said valve organ and separated therefrom and whose second extremity can be put in communication with said user unit; said valve organ comprising shutter means, movable between an extreme hermetic closure position and an open position of the outflow port of said feeding conduit, and provided with a first closure element and with a second closure element; said valve organ further comprising connecting means able to associate mutually and in a releasable manner said first closure element and second closure element making them mutually adherent, at least partially, along a plane of mutual substantial tangency and of mutual detachment.